Physics 451

Quantum mechanics I

Fall 2012

Karine Chesnel

• Class: M, W, F at 9 am C285 ESC

Physics 451Quantum Mechanics - Foundations

Instructor: Karine ChesnelN319 ESC801-422-5687kchesnel@byu.eduOffice hours: MWF 10-11am

Teaching assistant:Muxue Liuangela19881217@hotmail.com

A little bit about your teacher…

France

PhD in Physics

UniversityJoseph Fourier

MS in Physics Ecole

Normale Superieure

Post-DocLawrence Berkeley

Lab

BYU

A little bit about your teacher…

MagnetometryMagnetic microscopy

Our Lab

www.physics.byu.edu/faculty/chesnel/

• Textbook: David J. Griffiths

Introduction to Quantum Mechanics, 2nd ed.

• Get your CID:

www.physics.byu.edu/Courses/cid.aspx

• Register your I-clicker

Physics 451Quantum Mechanics - Foundations

Physics 451- schedule

Aug 27 – Sept 21

Exam I: Sep 24- Sep 27

Schrödinger equation Wave functionStationary statesHarmonic oscillator Infinite square wellFree particle

Oct 29 – Nov 16

Exam III: Nov 16- Nov 20

Schrödinger equationin spherical coordinatesHydrogen atomAngular momentumSpin

Nov 26 – Dec 5

Final Exam: W Dec 12, 7am

Two-particles systemsAtomsSolidsFinal review

Sep 26 – Oct 22

Delta function potentialFinite square wellFormalismUncertainty principle

Exam II: Oct 22 - Oct 25

APS Four corners Oct 26-27

Physics 451- Homework

• Homework twice a week: generally due T & Th 7pm

• Help sessions T & Th afternoons 3- 6 pm

• Return your homework in the Phys 451 slots across N373 ESC

• ALWAYS put your CID on first page of your work

• If you use computer softwares (Matlab, Maple, Mathematica…) to do a calculation, don’t forget to print and include all your actual work.

Physics 451 Help sessions

Help sessions on Tuesday & Thursday

from 3 to 6pm

room N 337 (undergraduate lab)

First session: this Thursday Aug 30

Physics 451 Homework

First homework assignment: next Friday Aug 31st by 7pm

Assignment # 1: Problems 1.1, 1.2, 1.3

In the textbook

Physics 451- Grading

• In class quizzes: 10%

• Homework: 40%

• Exams: 30%

• Final 20%

Check your grade during the semester:www.physics.byu.edu/Courses/Grades.aspx

Introduction toQuantum mechanics

Some History

ma F

Newton’s second Law Kinetic energy

21

2T mv

E T V Mechanical energy of the system

dpF

dt

Until 20th century: Classical Newtonian Mechanics…

Deterministic view: All the parameters of one particle can be determined exactly at any given time

Introduction toQuantum mechanics

Early 20th century: Some revolutionary ideas from bright minds…

Some History

Werner Heisenberg1901-1976

Uncertainty Principle

Erwin Schrödinger1887-1961

Schrödinger Equation

Wolfgang Pauli1900- 1958

Pauli exclusion principle

Introduction toQuantum mechanics

Essential ideas

1) Uncertainty principle: Conjugates quantities of a particle (ex: position & momentum)can not be known simultaneously within a certain accuracy limit

2) Quantization: The measurement of a physical quantity in a confined system results in quanta(the measured values are discrete)

3) Wave-particle duality: All particles can be described as waves (travelling both in space and in time)The state of the particle is given by a wave function ( , )x t

4) Extrapolation to classical mechanics: The laws of classical Newtonian mechanics are the extrapolation of thelaws of quantum mechanics for large systems with very large number of particles

Introduction toQuantum mechanics

Essential ideas

Schrödinger equation (1926)

2 2

22i V

t m x